diff --git a/sys/dev/dm/dm_pdev.c b/sys/dev/dm/dm_pdev.c
index 1f63d5f7da13..972122ebf691 100644
--- a/sys/dev/dm/dm_pdev.c
+++ b/sys/dev/dm/dm_pdev.c
@@ -1,4 +1,4 @@
-/*        $NetBSD: dm_pdev.c,v 1.16 2019/12/06 16:46:14 tkusumi Exp $      */
+/*        $NetBSD: dm_pdev.c,v 1.17 2019/12/07 06:26:31 tkusumi Exp $      */
 
 /*
  * Copyright (c) 2008 The NetBSD Foundation, Inc.
@@ -29,7 +29,7 @@
  * POSSIBILITY OF SUCH DAMAGE.
  */
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: dm_pdev.c,v 1.16 2019/12/06 16:46:14 tkusumi Exp $");
+__KERNEL_RCSID(0, "$NetBSD: dm_pdev.c,v 1.17 2019/12/07 06:26:31 tkusumi Exp $");
 
 #include <sys/types.h>
 #include <sys/param.h>
@@ -188,16 +188,16 @@ dm_pdev_rem(dm_pdev_t * dmp)
 int
 dm_pdev_destroy(void)
 {
-	dm_pdev_t *dm_pdev;
+	dm_pdev_t *dmp;
 
 	mutex_enter(&dm_pdev_mutex);
-	while (!SLIST_EMPTY(&dm_pdev_list)) {	/* List Deletion. */
-		dm_pdev = SLIST_FIRST(&dm_pdev_list);
 
-		SLIST_REMOVE_HEAD(&dm_pdev_list, next_pdev);
-
-		dm_pdev_rem(dm_pdev);
+	while ((dmp = SLIST_FIRST(&dm_pdev_list)) != NULL) {
+		SLIST_REMOVE(&dm_pdev_list, dmp, dm_pdev, next_pdev);
+		dm_pdev_rem(dmp);
 	}
+	KASSERT(SLIST_EMPTY(&dm_pdev_list));
+
 	mutex_exit(&dm_pdev_mutex);
 
 	mutex_destroy(&dm_pdev_mutex);
diff --git a/sys/dev/dm/dm_table.c b/sys/dev/dm/dm_table.c
index 54021558725d..47bbece0f515 100644
--- a/sys/dev/dm/dm_table.c
+++ b/sys/dev/dm/dm_table.c
@@ -1,4 +1,4 @@
-/*        $NetBSD: dm_table.c,v 1.10 2019/12/05 16:59:43 tkusumi Exp $      */
+/*        $NetBSD: dm_table.c,v 1.11 2019/12/07 06:26:31 tkusumi Exp $      */
 
 /*
  * Copyright (c) 2008 The NetBSD Foundation, Inc.
@@ -29,7 +29,7 @@
  * POSSIBILITY OF SUCH DAMAGE.
  */
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: dm_table.c,v 1.10 2019/12/05 16:59:43 tkusumi Exp $");
+__KERNEL_RCSID(0, "$NetBSD: dm_table.c,v 1.11 2019/12/07 06:26:31 tkusumi Exp $");
 
 #include <sys/types.h>
 #include <sys/param.h>
@@ -160,15 +160,14 @@ dm_table_destroy(dm_table_head_t * head, uint8_t table_id)
 
 	tbl = &head->tables[id];
 
-	while (!SLIST_EMPTY(tbl)) {	/* List Deletion. */
-		table_en = SLIST_FIRST(tbl);
+	while ((table_en = SLIST_FIRST(tbl)) != NULL) {
+		SLIST_REMOVE(tbl, table_en, dm_table_entry, next);
 		if (table_en->target->destroy(table_en) == 0)
 			table_en->target_config = NULL;
 
-		SLIST_REMOVE_HEAD(tbl, next);
-
 		kmem_free(table_en, sizeof(*table_en));
 	}
+	KASSERT(SLIST_EMPTY(tbl));
 
 	mutex_exit(&head->table_mtx);
 
diff --git a/sys/dev/dm/dm_target.c b/sys/dev/dm/dm_target.c
index 722b068b0e88..7b46adc2e9f1 100644
--- a/sys/dev/dm/dm_target.c
+++ b/sys/dev/dm/dm_target.c
@@ -1,4 +1,4 @@
-/*        $NetBSD: dm_target.c,v 1.23 2019/12/06 16:11:59 tkusumi Exp $      */
+/*        $NetBSD: dm_target.c,v 1.24 2019/12/07 06:26:31 tkusumi Exp $      */
 
 /*
  * Copyright (c) 2008 The NetBSD Foundation, Inc.
@@ -29,7 +29,7 @@
  * POSSIBILITY OF SUCH DAMAGE.
  */
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: dm_target.c,v 1.23 2019/12/06 16:11:59 tkusumi Exp $");
+__KERNEL_RCSID(0, "$NetBSD: dm_target.c,v 1.24 2019/12/07 06:26:31 tkusumi Exp $");
 
 #include <sys/types.h>
 #include <sys/param.h>
@@ -220,14 +220,13 @@ dm_target_destroy(void)
 	dm_target_t *dm_target;
 
 	mutex_enter(&dm_target_mutex);
-	while (TAILQ_FIRST(&dm_target_list) != NULL) {
-		dm_target = TAILQ_FIRST(&dm_target_list);
-
-		TAILQ_REMOVE(&dm_target_list, TAILQ_FIRST(&dm_target_list),
-		    dm_target_next);
 
+	while ((dm_target = TAILQ_FIRST(&dm_target_list)) != NULL) {
+		TAILQ_REMOVE(&dm_target_list, dm_target, dm_target_next);
 		(void)kmem_free(dm_target, sizeof(dm_target_t));
 	}
+	KASSERT(TAILQ_EMPTY(&dm_target_list));
+
 	mutex_exit(&dm_target_mutex);
 
 	mutex_destroy(&dm_target_mutex);